Millstone



(No Model.) l

T. L. STURTEVANT 8: W. H. ELLIS.

' MILLSTONE.

Patnted Nov. 26, 1895.

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UNITED STATES PATENT OFFICE.

THOMAS L. STURTEV ANT, OF FRAMINGHAM, AND IVILIIIAM II. ELLIS, OFBOSTON, MASSACHUSETTS.

MILLHSITONE.

SPECIFICATION forming part of Letters was No. 550,299, dated November26, 1 895. Application filed September 17,1892 $BIiEt1NO. 446,164.(NomodeL) To all whom it mag concern.-

Be it known that we, THOMAS L. STURTE- VANT, residingat Framingham, inthe county of Essex, and WILLIAM H. ELLIS, residing at Boston, in thecounty of Suffolk, State of Massachusetts, citizens of the UnitedStates, have invented certain new and useful Improvements in Millstones,of which the following is a specification.

Our invention relates particularly to composite millstones, such asshown in our Patent No. 483,504, dated September 27, 1892.

We have found in practice that it is highly important that specialprovision should be made for cutting out the furrows. We have heretoforeemployed furrow-strips interposed in the skirt, and wefind that, as arule, the material of which the furrow-strips are made should be softerthan the material forming the main body of the stone.

In constructing the improved millstone of our present invention we formthe furrowstrips of metal cast in suitably-shaped receptacles betweensections of the face of the skirt of the stone, and preferably we buildup the skirt of segmental sections that are united and mechanically heldtogether by metal cast in the spaces between the sections and formingthe furrow-strips. WVhere the segmental sections are formed of a metalor of a metal having embedded therein lumps or pieces of hardermaterial-such, for instance, as emery-the metal cast between thesections and that of the segmental sections may be such that they willunite or adhere with sufficient tenacity to properly mechanically securethe furrow-strips and sections of the skirt together. We may, however,provide the vertical faces of the segmental sections with recesses or soshape them that the cast metal furrow will mechanically interlock withthe segmental sections.

It is immaterial, so far as the scope of our invention is concerned,what material is employed to form the skirt or the bosom of the stone.lVe preferably use emery and zinc to form the skirt and construct it ofpreviouslyformed segmental sections, between which the metalfurrow-strips are cast. We may, however, form the skirt in other waysand of other materials, such as blocks of burstone or blocks of otherhard stone, and cast the furrow-strips between them. The bosom may beofburstone or any other suitable material, and in' some cases the bosommay be omitted. The cast furrow-strips may be of zinc or of zinccombined with emery or pieces of burstone, or of any suitable material,de pending on the material or combination of materials forming theskirt, since we desire that the furrow-strip shall be of softer materialthan the skirt.

In the accompanying drawings, illustrating our invention, Figure 1 is aplan view of a millstone embodying our improvements. Fig. 2 is a similarview of a modified form of millstone. Figs. 3, 4, and 5 illustratedifferent forms of segmental blocks used for constructing the skirt.

In Fig. 1 the stone is shown as composed of a bosom surrounding the eye,which may be of burstone or other: suitable stone, and the skirt iscomposed of segmental blocks of zinc or spelter and emery or iron andemery, or, in fact, emery may be employed with any suitable bindingmaterial, zinc or spelter being preferred.

The segments to form the skirt may be made separately and may be formedwith recessed sides-for instance, with concave sidesas shown in Fig. 3,with grooves a, as shown in Fig. 4, or with perforations b, as shown inFig.- 5. ments are placed within a ring A and around a burstone B,suitable spaces being left to receive the metal that forms thefurrow-strips (J. If zinc or like material is employed for forming thefurrow-strips, it is poured in between the segments D, and when it coolsand hardens will hold the segments at proper distances apart and will besecurely held in place by reason of the curved, grooved, or perforatedformation of the segments, as above eX- plained,'and as shown in Figs.3, 4, and 5. Fig. 2 shows substantially the same formation,except thatthere is no separately-formed bosom surrounding the eye, and a ring A isemployed to bound the inner ends of the segments and furrow-strips.

It is not essential, so far as parts of our invention are concerned,that the skirt of the stone should be made in sections. The stone Inconstructing the stone these seg-' may be constructed in the mannerdescribed in Letters Patent granted to Thomas L. Sturtevant September27, 1892-that is to say, the furrow-strips may be cast in receptacles ina continuous skirt.

One specific way of forming the stone which may be mentioned is thefollowing: The segments or skirt-sections, formed of zinc and smallblocks of emery, are placed in position 011 a plate P, Fig. 1. Anoutside temporary former or binding-band A is slipped in place aroundthem, and the bur bosom B is put in position, or when the bur bosom isnot used an iron band A, as shownin Fig. 2, takes its place. Spaces forthe furrow-strips are left between the segments, and. in these spaces weplace broken pieces of burstone and then pour in molten zinc, which, oncooling, binds the stone blocks firmly together. \Vhen the zinc is cool,we remove the temporary former, bind and shrink a permanent binding-bandabout the stone, which may then be turned over, and the side whichrested on the plate P before will have a sufficiently smooth face forwork.

lVe claim as our invention 1. A mill stone having a skirt composed ofpreviously-formed sections of grinding material, and metal cast betweenthe sections entering recesses in the sides thereof, and forming thefurrow strips, substantially as set forth.

2. A mill stone having a skirt formed of sections composed of metal withpieces or blocks of harder material, such as emery, embedded therein,and metal cast between the sections entering recesses in the sidesthereof and forming furrow strips, substantially as set forth.

3. A mill stone having a skirt formed of segmental sections composed ofcast metal with pieces or blocks of harder material embedded therein,and furrow strips of metal softer than the skirt sections cast betweensaid sections and entering recesses in the sides thereof, substantiallyas set forth.

4. A mill stone comprising a skirt made up of sections having recesseson their adjacent faces and metal furrow strips cast between them andfilling the recesses in them, substantially as set forth. i.

5. The millstone herein described, comprising an eye of burstone, askirt composed of segmental sections of blocks of emery and zinc, andfurrow strips composed of zinc and blocks of burstone.

6. The millstone herein described comprising a skirt composed ofsegmental sections, of blocks of emery and zinc, and furrow stripscomposed of zinc and blocks of burstone.

In testimony whereof We have hereunto subscribed our names.

THOMAS L. S'lUR'lEVAN'l. WILLIAM H. ELLIS.

\Vitnesses:

EDWARD H. MASON, MARY SHEEHAN.

